1. Field of the Invention
The subject invention generally pertains to electronic power conversion circuits, and, more specifically, to high frequency, switched mode electronic power converters. The subject matter relates to new isolated power converters which achieve higher efficiency at high and medium output voltages compared to prior art power converters.
2. Description of Related Art
The solution to the problem of converting power efficiently to high voltage loads has frequently relied on solutions that resemble the solutions typically used for medium and low voltages. Often a power conversion circuit such as a ZVS flyback converter, as illustrated in FIG. 1, is used to generate a relatively high voltage and the desired higher load voltage is generated with a chopper and a diode capacitance multiplier. The number of stages, efficiency, and complexity of the diode capacitance multiplier depends on the starting voltage, so it is important to generate as high a starting voltage as possible. In FIG. 1 the limiting factor to generating higher voltage is the voltage stress of DREC. In FIG. 1 the voltage stress of DREC is typically at least 2 times the output voltage, and the secondary winding stress of LMAIN is typically equal to or larger than the output voltage, depending largely on the line voltage range. What is needed is a simple high efficiency power converter that can generate higher voltages efficiently with a minimum of component voltage stress.